Metallocene catalyst component with good catalyst efficiency after aging

ABSTRACT

This invention relates to a syndiospecific metallocene of a substituted iPr[(cyclopentadienyl)(fluorenyl)]zirconium dichloride containing long-chain terminal alkene, for example octenyl groups, on fluorene at C2/C7. The metallocene compound useful as a catalyst in the present invention is described by the general formula: 
     
         R&#34;(C.sub.5 H.sub.4)(C.sub.4 H.sub.4-m R&#39;.sub.m C.sub.5 C.sub.4 H.sub.4-n 
    
      R&#39; n )MeQ p   
     wherein (C 5  H 4 ) is a cyclopentadienyl ring and (C 4  H 4-m  R&#39; m  C 5  C 4  H 4-n  R&#39; n ) is a fluorenyl radical; R&#39; is a long chain alkene substituent having 514 20 carbon atoms on the fluorene ligand at C2 or C7, each R&#39; may be the same or different; R&#34; is a structural bridge between the (C 5  H 4 ) and (C 4  H 4-m  R&#39; m  C 5  C 4  H 4-n  R&#39; n ) rings to impart stereorigidity; Q is a hydrocarbon radical or a halogen; Me is a Group IIIB, IVB, VB, or VIB metal; m=0 or 1; n=1; and p is the valence of Me minus 2. Polymerizations with metallocene/MAO solutions stored at room temperature under nitrogen for several days resulted in gradual increases in polymer yields when using the metallocene of the present invention and a decrease in polymer yield when using metallocne of the prior art.

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

This invention relates to a metallocene catalyst component for olefinpolymerization, specifically, to a syndiospecific metallocene catalystcomponent having a polymerizable functional group substituent.

2. DESCRIPTION OF THE PRIOR ART

German patent application 2,608,863 discloses a catalyst system for thepolymerization of ethylene consisting of bis(cyclopentadienyl)-titaniumdialkyl, an aluminum trialkyl and water. German patent application2,608,933 disclosed an ethylene polymerization catalyst systemconsisting of zirconium metallocenes of the general formula(cyclopentadienyl)_(n) Zr Y_(4-n), wherein Y represents R₁ CH₂ AlR₂, CH₃CH₂ AlR₂ and CH₃ CH (AlR₂)₂ wherein R stands for an alkyl ormetallo-alkyl, and n is a number within the range 1-4; and themetallocene catalyst is in combination with an aluminum trialkylcocatalyst and water.

The use of metallocenes as catalysts in the copolymerization of ethyleneand other alpha-olefins is also known in the art. U.S. Pat. No.4,542,199 to Kaminsky, et al. disclosed a process for the polymerizationof olefins and particularly for the preparation of polyethylene andcopolymers of polyethylene and other alphaolefins. The disclosedcatalyst system includes a catalyst of the formula (cyclopentadienyl)₂MeRHal in which R is a halogen, a cyclopentadienyl or a C₁ -C₆ alkylradical, Me is a transition metal, in particular zirconium, and Hal is ahalogen, in particular chlorine. The catalyst system also includes analuminoxane having the general formula Al₂ OR₄ (Al(R)--O)_(n) for alinear molecule and/or (Al(R)--O)_(n+2) for a cyclic molecule in which nis a number from 4-20 and R is a methyl or ethyl moiety. A similarcatalyst system is disclosed in U.S. Pat. No. 4,404,344.

U.S. Pat. No. 4,530,914 discloses a catalyst system for thepolymerization of ethylene to polyethylene having a broad molecularweight distribution and especially a bimodal or multimodal molecularweight distribution. The catalyst system is comprised of at least twodifferent metallocenes and an alumoxane. The patent disclosesmetallocenes that may have a bridge serving to make the ringsstereorigid. The bridge is disclosed as being a C₁ -C₄ alkylene radical,a dialkyl germanium or silicon, or an alkyl phosphine or amine radical.

European patent Application 0185918 discloses a stereorigid, chiralmetallocene catalyst for the polymerization of olefins. The bridgebetween the cyclopentadienyl groups is disclosed as being a linearhydrocarbon with 1-4 carbon atoms or a cyclical hydrocarbon with 3-6carbon atoms. The application discloses zirconium as the transitionmetal used in the catalyst, and linear or cyclic alumoxane is used as aco-catalyst. It is disclosed that the system produces a polymer productwith a high isotactic index.

Catalysts that produce isotactic polyolefins are disclosed in copendingU.S. patent application Ser. No. 317,089 filed Feb. 28, 1989, and U.S.Pat. Nos. 4,794,096 and 4,975,403. This application and these patentsdisclosed chiral, stereorigid metallocene catalyst components that areused in the polymerization of olefins to form isotactic polymers and areespecially useful in the preparation of a highly isotacticpolypropylene.

Catalysts that produce syndiotactic polyolefins are disclosed in U.S.Pat. No. 4,892,851. Many metallocenes consisting of deliberatestructural modifications to a syndiospecific catalyst, namely,isopropyl[(cyclopentadienyl)(fluorenyl)]zirconium dichloride, asdisclosed in U.S. Pat. No. 4,892,851 (hereinafter referred to asiPr[(Cp)(Flu)]ZrCl₂). The structural modifications have been correlatedwith polymer properties. Some of the polymer properties which can bevery effectively controlled by catalyst structure modifications includemolecular weight, melting point and the microstructure. However, all themodifications to the iPr[(Cp)(Flu)]ZrCl₂ have resulted in a decrease inthe catalyst efficiency compared to the unsubstituted complex under anygiven set of polymerization conditions. So far, there have not been anyefforts made to use substituent effects for manipulating polymerizationefficiencies of the metallocenes.

SUMMARY OF THE INVENTION

A syndiospecific metallocene of a substitutedisopropyl[(cyclopentadienyl)(fluorenyl)]zirconium dichloride containinglong-chain terminal alkene (hereinafter referred to as "diolefincatalyst"), for example octenyl groups, on fluorene at C2/C7 wassynthesized. The alkene functionality can, in principle, beselfpolymerized by the catalyst in presence of cocatalysts such as MAO,or it can be co-polymerized with propylene thus supporting the catalystin a polypropylene matrix.

The metallocene compound useful as a catalyst in the present inventionis described by the general formula:

    R"(C.sub.5 H.sub.4)(C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n)MeQ.sub.p

wherein (C₅ H₄) is a cyclopentadienyl ring and (C₄ H_(4-m) R'_(m) C₅ C₄H_(4-n) R'_(n)) is a fluorenyl radical; R' is a long chain alkenesubstituent having 5-20 carbon atoms on the fluorene ligand at C2 or C7,each R' may be the same or different; R" is a structural bridge betweenthe (C₅ H₄) and (C₄ H_(4-m) R'_(m) C₅ C₄ H_(4-n) R'_(n)) rings to impartstereorigidity; Q is a hydrocarbon radical or a halogen; Me is a GroupIIIB, IVB, VB, or VIB metal; m=0 or 1; n=1; and p is the valence of Meminus 2.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings in which like numerals in different figuresrepresent the same structures or elements wherein:

FIG. 1 is a synthesis scheme for producingisopropyl[(cyclopentadienyl)(fluorenyl)]zirconium dichloride typecontaining long chain alkene substituents on the fluorenyl ring.

FIG. 2 is the proton NMR spectrum of 2,7-diiodofluorene.

FIG. 3 is the proton NMR spectrum of 2,7-di-l-octen-8-yl fluorene.

FIG. 4 is the proton NMR spectrum of isopropyl(cyclopentadienyl)(2,7-di-l-octen-8-yl fluorene).

FIG. 5 is the proton NMR spectrum of isopropyl(cyclopentadienyl)(2,7-di-octen-8-ylfluorenyl) zirconium dichloride.

DETAILED DESCRIPTION OF THE INVENTION

The syndiospecific catalyst iPr[(Cp)(Flu)]ZrCl₂ is disclosed in U.S.Pat. No. 4,892,851. Introduction of long chain olefinterminated alkylgroups at C2 and C7 of fluorene in iPr[(Cp)(Flu)]ZrCl₂ retains thesyndiospecificity of the metallocene. However, the new catalyst is lessactive and less stereospecific than iPr[(Cp)(Flu)]ZrCl₂ and givespolymer of lower molecular weight. This may be in part due to thecoordination of side chain carbon-carbon double bonds to zirconium thuscompeting for coordination with propylene. Also contributing to thedecreased catalyst efficiency is the general effect of any substituentat these positions.

The metallocene compounds useful in the present invention is describedby the general formula:

    R"(C.sub.5 H.sub.4)(C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n)MeQ.sub.p

wherein (C₅ H₄) is a cyclopentadienyl ring and (C₄ H_(4-m) R'_(m) C₅ C₄H_(4-n) R'_(n)) is a fluorenyl radical; R' is a long chain alkenesubstituent having 5-20 carbon atoms on the fluorene ligand at C2 or C7,each R' may be the same or different; R" is a structural bridge betweenthe (C₅ H₄) and (C₄ H_(4-m) R'_(m) C₅ C₄ H_(4-n) R'_(n)) rings to impartstereorigidity; Q is a hydrocarbon radical or a halogen; Me is a GroupIIIB, IVB, VB, or VIB metal; m=0 or 1; n=1; and p is the valence of Meminus 2. Preferably, R' is the same. Preferably, R' is a long chainalkene substituent having 6-10 carbon atoms on the fluorene ligand at C2or C7, and, more preferably is octenyl. Preferably, Me is a Group IVBmetal, more preferably is titanium, zirconium or hafnium and, mostpreferably is zirconium. Preferably, Q is chlorine. Preferably, R" isselected from the group consisting of a substituted or unsubstitutedalkyl radical having 1-4 carbon atoms as the bridging component andsubstituents of hydrocarbyl radicals having 1-10 carbon atoms or acompound containing silicon, germanium, phosphorus, nitrogen, boron oraluminum as the bridging component and substituents of hydrocarbylradicals having 1-10 carbon atoms, more preferably, a methylene,ethylene, isopropyl, diphenylmethyl or dimethylsilyl radical and, mostpreferably, an isopropyl radical. This isopropyl radical is alsodescribed as a dimethyl-substituted methyl radical, having one carbon asthe bridging component and two methyl substituents. A specific exampleof the metallocene compound useful in the present invention isisopropyl(cyclopentadienyl)(2,7-di1-octen-8-ylfluorenyl)zirconiumdichloride.

A catalyst system using the metallocene compound disclosed above can beformed with a cocatalyst. The preferred cocatalyst is an organoaluminumcompound of the general formula (R-Al-O) in the cyclic form andR(R-Al-O)_(n) AlR₂ in the linear form wherein R is an alkyl group with1-5 carbons and n is an integer from about 1 to about 20. Preferably,the organoaluminum compound is an aluminoxane and, more preferably, ismethylalumoxane (MAO).

The most significant feature of the diolefin catalyst is the effect ofits aging process with aluminoxane solutions on the polymerizationyields and polymer properties. The polymer yields were more than doubledby the aging process. Accompanying the increased polymer yields areincreased polymer molecular weight, melting point and bulk density.These observations suggest that the catalysts containing polymerizableolefinic groups represent new class of syndiospecific metallocenes.

The invention having been generally described, the following examplesare given as particular embodiments of the invention and to demonstratethe practice and advantages thereof. It is understood that the examplesare given by way of illustration and are not intended to limit thespecification or the claims to follow in any manner.

The catalyst synthesis was achieved in a multi-step synthesis asdescribed below in FIG. 1.

i. synthesis of 2,7-diiodofluorene (2)

ii. synthesis of 1-octenyl-8-BBN (3)

iii. synthesis of 2,7-di-1-octen-8-ylfluorene (4)

iv. synthesis ofisopropyl(cyclopentadienyl)(2,7-di-1-octen-8-ylfluorene) (5)

v. synthesis of isopropyl(cyclopentadienyl)(2,7-di-1-octen-8-ylfluorene)zirconium dichloride (6)

i. Synthesis of 2,7-diiodofluorene (2)

The procedure disclosed in Ogata, y., Urasaki, I. J. Chem. Soc 1970, 121689, 1691 was used to prepare 2,7-diiodofluorene from fluorene andiodine. To a stirred solution of fluorene (5.0 g, 0.03 mol) and iodine(9.1 g, 0.036 mol) in 180 ml acetic acid was added at 50° C. dropwiseperacetic acid (4.7M, 5.1 ml, 0.03 mol) over 6 hours. Precipitation ofoff-white solid occurred three hours after the addition of peroxide wasstarted. The reaction mixture was allowed to cool down with ice-bath andthe solid was filtered. The solid was washed with a solution ofpotassium iodide and sodium bisulfite, followed by water. The proton NMRspectrum (FIG. 2) agrees well with the expected structure.

ii. Synthesis of 1-octenyl-9-BBN (3)

The procedure disclosed in Chung, T. C. et al. Macromolecules, 1988, 21,865 was used to prepare the title compound from 1,7-octadiene and 9-BBN.A 500 ml round bottom flask equipped with addition funnel was chargedwith 60 ml 1,7-octadiene. A solution of 9-BBN dimer (100 mmol) in 200 mlanhydrous tetrahydrofuran (THF) was added dropwise at room temperatureand stirred overnight. The solvent and excess diene were removed bydistillation at 60°-70° C. and 10 mtorr. The remaining liquid wasdistilled at 120°-140° C. and 10 mtorr. The yield was 18.8 g. The liquidis an air-sensitive, and pyrophoric material.

iii. Synthesis of 2,7-di-(1-octen-8-yl)fluorene (4)

The general procedure described in Suzuki, A., et al J. Am. Chem. Soc.1989, 111, 314 for coupling of aryl iodides withB-alkyl-9-borabicyclononane derivatives using organopalladium catalystwas followed.

To a suspension of 5.0 g (0.012 mol) of diiodofluorene (1), 0.25 gbis(triphenylphosphine) palladium dichloride, 6.60 g potassium carbonatein 300 ml anhydrous DMF, was added a THF (3 ml) solution of1-octene-8-BBN (2) under argon. The mixture was heated to 50° C.overnight. The solvents were removed by vacuum distillation. The residuewas extracted with hexane and the extracts were passed through short bedof neutral alumina and eluted with hexane. Removal of hexane yielded 4as a white solid. The product was characterized by proton NMR (FIG. 3).

iv. Synthesis of isopropyl(2,7dioctenylfluorenyl)(cyclopentadienyl) (5)

To a solution of dioctenylfluorene 3 (2.0 g, 5.2 mmol) in dry ether (100ml) kept at 0° C., a 1.4M solution of methyllithium in ether was addedand stirred overnight at room temperature. The resulting yellow solutionwas cooled to -50° C. and a solution of 6,6-dimethylfulvene (0.82 ml,6.8 mmol) in dry THF was added dropwise; the reaction mixture allowed towarm to room temperature and stirred overnight. Additional amount of THF(20 ml) was added and the reaction mixture was concentrated by passing agentle stream of argon for 18 hours. The solvents were removed undervacuum and a mixture of hexane and dilute hydrochloric acid were added.The layers were separated and the aqueous layer was extracted twice withether. The combined organic layers were washed with water followed bysaturated sodium chloride solution and dried over anhydrous MgSO₄. Thesolvents were removed in vacuo; the resulting oil was successivelychromatographed on neutral alumina and silica gel and eluted with 1:1mixture of methylene chloride and hexane to obtain the ligand as anorange oil. Proton NMR spectrum (FIG. 4) confirmed the expectedstructures for the isomeric ligand mixture.

v. Synthesis of isopropyl(cyclopentadienyl)(2,7-di-1-octen-8-ylfluorenyl)zirconium dichloride (6)

To a solution of 1.2 g of the ligand 4 in anhydrous THF (50 ml), a 1.4Msolution of methyllithium in ether (3.6 ml) was added and stirredovernight. The solvents were removed from the dark red solution underhigh vacuum to obtain a dark red oil. The flask was cooled to -78° C.,and methylene chloride prechilled to -78° C. was cannulated in andstirred. A slurry of ZrCl₄ (0.5 g, 2.1 mmol) in methylene chlorideprechilled to -78° C. was cannulated into the dianion solution. Thetemperature was allowed to slowly warm up to room temperature andstirring was continued to 3 hours. The methylene chloride was removedunder high vacuum, the solid was taken into the drybox andrecrystallized in small batches. The crude product was washed withhexane; the hexane layers discarded. The hexane insoluble solid wasdissolved in dry methylene chloride and filtered. The solvent wasremoved under high vacuum, to obtain 5 as an orange solid which wasessentially pure as judged by proton NMR (FIG. 5).

PROCEDURES FOR AGING CATALYST/ALUMOXANE SOLUTIONS Method A

A weighed amount of the catalyst was dissolved in less than requiredamount of MAO in heptane or MAO in toluene and the solution was kept ina Wheaton bottle wrapped in aluminum foil and stored inside the dryboxeither at room temperature or at 0° C. An aliquot was taken at regularintervals; diluted with additional amount alumoxane and thepolymerization was run.

Method B

A weighed amount of the catalyst was dissolved in required amount ofalumoxane and stored in the drybox at specified temperature away fromlight. A 5 ml aliquot was taken at regular intervals and polymerizationswere run.

Method C

A weighed amount of the catalyst was dissolved in MAO in heptane andheated to 50° C. for one hour under nitrogen and the polymerization wasrun.

POLYMERIZATIONS

All the polymerizations were run in bulk propylene (1.4 L) in amagnedrive, packless Zipperclave reactor. The catalyst/alumoxanesolution taken in a stainless steel sample cylinder was charged alongwith 400 ml propylene into the reactor containing 1 liter propylene atroom temperature. Stirring at 1200 rpm was started and the temperaturewas raised to 60° C. within 5 minutes. The stirring was decreased to 300rpm and the polymerization was run for one hour. The temperature of thereactor was lowered to room temperature. The monomer was vented, thereactor was opened and polymer fluff was collected. Any polymer ringaround and stirrer and baffles was collected separately and weighed. Thepolymer which stuck to the reactor walls and the stirrer was extractedwith toluene at 90° C. and precipitated by the addition of methanol. Theprecipitated polymer was filtered, dried and weighed. The sum of thepolymer obtained from the ring and toluene extraction was defined asfouling.

                                      TABLE 1                                     __________________________________________________________________________    Comparison of Polymerization Data Obtained with the Diolefin Catalyst         Using "MAO in heptane" and "Schering MAO" with "MAO in toluene"               or Schering MAO Under Standard Conditions                                          Catalyst (mg)/        Melt                                                    Alumoxane                                                                             Poly. T                                                                            Total                                                                              Effic.                                                                            pt Mw/1000  BD                                     Example                                                                            (ml)    C    yield(g)                                                                           g/g-h                                                                             °C.                                                                       (gpc)                                                                              MWD g/cc                                                                             % Fouling                           __________________________________________________________________________    1    2.0/5.0 60   26   13000                                                                             126                                                                              57.1 2.4 0.17                                                                             46                                       MAO in                                                                        toluene                                                                  2    2.0/5.0 60   29   14500                                                                             128                                                                              --   --  0.24                                                                             48                                       MAO in                                                                        toluene                                                                  3    2.0/5.0 30    6    3000                                                                             134                                                                              97.2 2.8 <0.10                                                                            <5                                       MAO in                                                                        toluene                                                                  4    2.0/5.0 60   72   36000                                                                             126                                                                              56.3 2.3 0.22                                                                             32                                       MMAO in                                                                       heptane                                                                  __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    Polymerization Data With MAO in Toluene Solutions of The Diolefin             Catalyst                                                                      Aged.sup.1 at Room Temperature                                                                Poly.          MW/                                                 Catalyst (mg)/                                                                        Age                                                                              wt Effic.                                                                            % Effic                                                                            DSC                                                                              1000     BD                                    Example                                                                            MAO (ml)                                                                              (hr)                                                                             (g)                                                                              g/g-h                                                                             increase                                                                           °C.                                                                       (gpc)                                                                              MWD g/ml                                                                             % Fouling.sup.4                    __________________________________________________________________________    5    2.0/5.0  0 26 13000                                                                             --   126                                                                              57.1 2.4 0.16                                                                             52                                 6    2.0/5.0 24.sup.                                                                          45 22500                                                                             72   129                                                                              68.6 2.6 0.27                                                                             42                                 7    2.0/5.0 48.sup.2                                                                         80 40000                                                                             210  130                                                                              113.5                                                                              3.2 0.29                                                                             90                                 8    2.0/5.0 72.sup.                                                                          58 29000                                                                             120  130                                                                              70.5 2.8 0.26                                                                             91                                 9    2.0/5.0 96.sup.3                                                                         37 18500                                                                             42   130                                                                              72.5 2.5 n.d..sup.5                                                                       100                                __________________________________________________________________________     .sup.1 A stock solution of the catalyst was made in MAO in Toluene a          Wheaton bottle, wrapped in aluminum foil and stored at room temperature       inside the dry box.                                                           .sup.2 The original purple color of the stock solution changed to red         purple.                                                                        .sup.3 The stock solution color changed to brown.                            .sup.4 Fouling was calculated by adding the weight of the ring and weight     of toluene extract and dividing the sum by the total yield.                   .sup.5 n.d.  not determined.                                             

                                      TABLE 3                                     __________________________________________________________________________    Bulk Polymerization Data with MAO in Toluene                                  Solutions of the Diolefin Catalyst Aged at 0° C.                           Catalyst (mg)/                                                                        Age  Poly.                                                                            Effic.                                                                            DSC                                                                              Mw/1000                                            Run #                                                                             MAO (ml)                                                                              Period(h)                                                                          wt (g)                                                                           g/g-h                                                                             °C.                                                                       (gpc)                                                                              MWD % Fouling.sup.1                           __________________________________________________________________________    10  2.0/5.0 24   23 11500                                                                             128                                                                              54.6 3.7  91                                       11  2.0/5.0 48   19 9500                                                                              129                                                                              56.4 4.0 100                                       12  2.0/5.0 72   10 5000                                                                              128                                                                              n.d  n.d 100                                       __________________________________________________________________________     .sup.1 Fouling was calculated by adding the weight of the ring and weight     of Toluene extract and dividing the sum by the total yield.              

                                      TABLE 4                                     __________________________________________________________________________    Bulk Polymerization Data with MMAO in heptane                                 Solutions of the Diolefin Catalyst Aged at Room Temperature                   and at 50° C.                                                              Cat. (mg)                                                                           Age  Aging Poly.                                                                             Effic.                                                                            DSC                                                                              Mw/1000  B.D                                  Run #                                                                             MAO (ml)                                                                            Time (h)                                                                           Temp (C)                                                                            wt (g)                                                                            g/g-h                                                                             (°C.)                                                                     (gpc)                                                                              MWD g/cc                                 __________________________________________________________________________    13  2.0/5.0                                                                             0    24    72  36000                                                                             126                                                                              56   2.3 0.22                                 14  2.0/5.0                                                                             24.sup.1.sup.                                                                      24    104 52000                                                                             129                                                                              67   2.7 n.d                                  15  1.0/5.0.sup.2                                                                       24   24    87  87000                                                                             129                                                                              75   2.8 n.d                                  16  1.6/5.0.sup.3                                                                       1    50    61  38000                                                                             128                                                                              77   2.7 n.d                                  __________________________________________________________________________     .sup.1 The original light purple solution of the MAO in heptane solution      of the catalyst turned to golden brown in 24 hours.                           .sup.2 3.0 mg of the catalyst was dissolved in 5 ml "MAO in heptane" and      "MMAO" with "MAO in heptane" aged for 24 hours; an aliquot of 1.6 ml          (approx. 1 mg catalyst) was taken and diluted with 3.4 ml MMAO and the        polymerization was run.                                                       .sup.3 A solution of the catalyst (1.6 mg) and MAO in heptane (5 ml) was      heated for one hour at 50° C. in a Wheaton bottle, cooled and          injected into the reactor.                                               

                                      TABLE 5                                     __________________________________________________________________________    Bulk Polymerization Data with MAO in Toluene Solutions if                     "iPr(Flu-Cp)]ZrCl2" with                                                      "iPr[(Cp)(Flu)]ZrCl.sub.2 aged at room temperature                            Compare                                                                            Catalyst (mg)/                                                                        Age  Poly.                                                                             Effic.                                                                            DSC                                                                              Mw/1000  BD                                      Example                                                                            MAO (ml)                                                                              time (hr)                                                                          wt (g)                                                                            g/g-h                                                                             (°C.)                                                                     (gpc)                                                                              MWD g/cc                                                                             % Fouling                            __________________________________________________________________________    1    0.50/5.0                                                                               0   145 290000                                                                            136                                                                              85.0 2.5 0.17                                                                              7.4                                 2    0.5/5.0 24   155 310000                                                                            138                                                                              87.6 2.6 0.16                                                                             20.0                                 3    0.5/5.0 48   104 208000                                                                            138                                                                              89.5 2.4 0.18                                                                             39.0                                 4    0.5/5.0 72   113 226000                                                                            137                                                                              87.6 2.4 0.21                                                                             38.0                                 __________________________________________________________________________     All the runs except Comparative Example 4 were run from the same batch of     stock solution of iPr[(Cp)(Flu)]ZrCl2. The 72 hour polymerization             (Comparative Example 4) was run with a solution made and aged separately.

                                      TABLE 6                                     __________________________________________________________________________    Bulk Polymerization Data with MAO in Toluene Solutions if                     iPr[(Cp)(Flu)]ZrCl.sub.2                                                      Aged at 0° C.                                                          Compare                                                                            Catalyst (mg)                                                                        Age Poly.                                                                             Effic.                                                                            DSC                                                                              Mw/1000  BD                                        Example                                                                            MAO (ml)                                                                             time(h)                                                                           wt(g)                                                                             g/g-h                                                                             (°C.)                                                                     (gpc)                                                                              MWD g/cc                                                                             % Fouling                              __________________________________________________________________________    5    0.5/5.0                                                                               0  145 290000                                                                            136                                                                              85.4 2.5 0.17                                                                              7                                     6    0.5/5.0                                                                              24  137 274000                                                                            137                                                                              89.6 2.4 0.16                                                                             30                                     7    0.5/5.0                                                                              48  109 218000                                                                            137                                                                              89.6 2.4 0.17                                                                             35                                     8    0.5/5.0                                                                              72  129 258000                                                                            136                                                                              88.4 2.5 0.15                                                                             29                                     __________________________________________________________________________     All polymerizations except Comparative Example 8 were run from the same       stock solution. MAO in Toluene catalyst solution for Comparative Example      was made separately and aged for 72 hours.                               

Comparison of polymerization data obtained with iPr[(Cp)(Flu)]ZrCl₂(Tables 5 and 6) and the diolefin catalyst at 60° C. (Tables 2 and 3)indicates that the diolefin catalyst is less efficient and lessstereospecific than iPr[(Cp)(Flu)]ZrCl₂. All the results from the agingstudies point to the conclusion that the new catalyst isself-polymerizing in the presence of MAO. Aged diolefin catalyst/MAOsolution increased the bulk density of the polymer but the reactorfouling remained high.

Much of the polymerization work with the diolefin catalyst was concernedwith the reactivity of the olefin groups on the side chains under thepolymerization conditions. Polymerizations with catalyst/MAO stocksolutions stored at room temperature under nitrogen for several daysresulted in gradual increases in polymer yields over a three day periodand then gradually the yields decreased (Table 2). In parallel withincrease in polymer yields with aging of MAO/catalyst solutions, therewas a simultaneous increase in polymer molecular weight, molecularweight distribution, melting point and bulk density. After prolongedperiod of aging (>48 h), a decrease in these polymer property valueswith the exception of melting point occurred simultaneously with adecrease in polymer yields. The decrease in polymer yield with prolongedaging appears to be due to catalyst decomposition as evidenced by changein the purple color of the catalyst/MAO solutions to brown accompaniedby deposition of insoluble solids.

The aging temperature also had significant effect on polymerizationbehavior of the diolefin catalyst. When the aging temperature was 0° C.,the polymer yields dropped gradually with no significant changes inpolymer properties (Table 3). The color of the catalyst/MAO solutionchanges from purple to pink during the aging period, indicatingstructural changes. The difference in efficiencies of the catalystsystems aged at room temperature and at 0° C. suggest that the chemicalreactions, possibly polymerization, undergone by the olefin functionalgroups on the side chains at room temperature do not take place at 0° C.

The polymerization studies with the diolefin catalyst/MAO in heptane inaddition to room temperature aging, elevated temperature (50° C.) agingalso (Table 4). Better polymer yields were obtained with MAO in heptanethan with MAO in toluene. Interestingly, the purple color of thecatalyst/MAO in heptane solution turned to yellow after storing thesolution at room temperature for 24 hours. Heating the diolefincatalyst/MAO in heptane solution for one hour under nitrogen, changedthe color from purple to yellow. The polymer yield did not decreasebecause of the heating. The significance of the color changes with MAOin heptane is not clear.

Results obtained from the aging studies with iPr[(Cp)(Flu)ZrCl₂ /MAO ineither heptane or toluene solutions (Tables 5-6) present interestingcomparison with the above results and serve to show that the diolefincatalyst belongs to a class of metallocenes different fromiPr[(Cp)(Flu)]ZrCl₂.

The changes in catalyst activity with aging can be rationalized in termsof in situ polymerization of the olefin groups by the active form of themetallocene in MAO. This phenomenon could be initiated eitherintermolecularly or intramolecularly. As is true with metallocenecatalyzed alpha-olefin polymerizations, the rate of polymerization isgreater at elevated temperature. This would explain the differences inpolymerization efficiencies with MAO solutions of diolefin catalyst agedat room temperature and at 0° C.

The gradual increase in catalytic activity over a period of several daysis consistent with slow rate of polymerization of alpha-olefins largerthan propylene by metallocenes such as iPr[(Cp)(Flu)]ZrCl₂. It is quitelikely that the side chain olefin groups in the cationic metallocene(produced immediately after dissolving the dichloride complex in MAO)are pi-complexed to the zirconium either intra- or inter-molecularly.Such internal complexation of olefins to the active metal center makesthe metal center less available to propylene coordination, thusdecreasing catalyst efficiency. Such internal coordination may also playa role in decreasing the polymer molecular weight and melting point.Removal of such internal coordination by polymerizing the side chainolefins provides for efficient and free access of propylene tozirconium.

The proposed polymeric catalyst system is expected to be heterogeneousin composition because of different ways the two internal olefins can bepolymerized with other catalyst units. The heterogeneous nature of thepolymerized catalyst is likely to be responsible for the increase in MWDand also increased bulk density of the polymer obtained with thecatalyst solutions aged for 48 hours.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed as new and desired to be secured by letter of patent ofthe United States is:
 1. A catalyst system for polymerizing olefins ofthree or more carbon atoms to produce a syndiotactic polyolefin havingimproved aging comprising:a) a metallocene compound described by thegeneral formula:

    R"(C.sub.5 H.sub.4)(C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n)MeQ.sub.p

wherein (C₅ H₄) is a cyclopentadienyl ring and (C₄ H_(4-m) R'_(m) C₅ C₄H_(4-n) R'_(n)) is a fluorenyl radical; R' is a long chain alkenesubstituent having 5-20 carbon atoms on the fluorene ligand at C2 or C7individually or both C2 and C7, each R' being the same or different; R"is a structural bridge between the (C₅ H₄) and (C₄ H_(4-m) R'_(m) C₅ C₄H_(4-n) R'_(n)) rings to impart stereorigidity; Q is a hydrocarbonradical or a halogen; Me is a Group IIIB, IVB, VB, or VIB metal; m=0 or1; n=1; and p is the valence of Me minus 2; and b) an aluminoxane.
 2. Acatalyst system as recited in claim 1 wherein the cocatalyst is analuminoxane of the general formula (R-Al-O) in the cyclic form andR(R-Al-O)_(n) AlR₂ in the linear form wherein R is an alkyl group with1-5 carbons and n is an integer from about 1 to about
 20. 3. A catalystsystem as recited in claim 1 wherein the aluminoxane is methylalumoxane.4. A catalyst system as recited in claim 1 wherein R' is at both C2 andC7.
 5. A catalyst system as recited in claim 4 wherein R' is the same.6. A catalyst system as recited in claim 1 wherein R' is a long chainalkene substituent having 6-10 carbon atoms.
 7. A catalyst system asrecited in claim 1 wherein R' is octenyl.
 8. A catalyst system asrecited in claim 1 wherein the metallocene compound isiPr(2,7-di-1-octen-8-ylfluorenyl)(Cp)ZrCl₂.
 9. A catalyst system asrecited in claim 1 wherein Me is a Group IVB metal.
 10. A catalystsystem as recited in claim 1 wherein Me selected from the groupconsisting of titanium, zirconium and hafnium.
 11. A catalyst system asrecited in claim 1 wherein Me is zirconium.
 12. A catalyst system asrecited in claim 1 wherein Q is chlorine.
 13. A catalyst system asrecited in claim 1 wherein R" is selected from the group consisting of asubstituted or unsubstituted alkyl radical having 1-4 carbon atoms asthe bridging component and substituents of hydrocarbyl radicals having1-10 carbon atoms or a compound containing silicon, germanium,phosphorus, nitrogen, boron or aluminum as the bridging component andsubstituents of hydrocarbyl radicals having 1-10 carbon atoms.
 14. Acatalyst system as recited in claim 1 wherein R" is a selected from thegroup consisting of a methylene radical, a ethylene radical, anisopropyl radical and a dimethylsilyl radical.
 15. A catalyst system asrecited in claim 1 wherein R" is an isopropyl radical.